Before the crew boards the aircraft for a commercial airline flight, is there anyone who checks the instruments and avionics system? I'm sure the engines are checked but what about the avionics systems, instruments, sensors,etc.?

There was an accident due to an incorrect reading of the pitot sensor, is there somebody to check it?

  • $\begingroup$ Maintenance operations have specific checks by the maintenance team. Maintenance operations, and inoperative systems are tracked in a log which is read by the crew when they get the aircraft. There is no reason to expect sudden system failures between flights. When no maintenance is required, the crew performs normal procedures to activate systems. The captain performs a visual check of the aircraft, the pre-flight walk-around. The copilot / first officer is usually in charge of setting the cockpit before the first flight of the day. Readings are cross-checked for compliance. $\endgroup$
    – mins
    Jun 11, 2015 at 6:19
  • 3
    $\begingroup$ If you can provide more information about the accident you mention, so that the flight can be identified, then we may provide additional details about possible errors in detecting malfunction, based on the safety board report. $\endgroup$
    – mins
    Jun 11, 2015 at 6:23
  • $\begingroup$ Why specifically "before crew board the aircraft"? $\endgroup$
    – Jan Hudec
    Jun 11, 2015 at 7:05
  • $\begingroup$ In the accident ,captain's instrument and first officer's instruments showed different reading,this was due to one of the pico sensor was blocked with mud before flight, both of crew where confused,even autopilot system couldn't work because of two entirely different reading,i don't remember the aircraft information $\endgroup$
    – fawaz
    Jun 11, 2015 at 9:08
  • $\begingroup$ Both of the crew did not analyze the instruments ,actually they didn't compare the instruments,RIP both of them $\endgroup$
    – fawaz
    Jun 11, 2015 at 9:13

3 Answers 3


In general, nobody else does.

When pilots arrive to an aircraft for the first flight of the day, extra checks are performed by the crew to verify aircraft systems are all working properly. These checks are done once per day and subsequent flights will perform abbreviated checks instead. A visual walk around inspection is accomplished before and after every flight.

Maintenance will check on airplanes at required intervals but outside of specific checks (associated with the carriers approved maintenance program) the only time they'll check something like a pitot tube is if the crew notes a problem and writes it up. At that point maintenance will address the issue to return the aircraft to airworthiness.


Before crew board the aircraft for a commercial airline, is there any person who checks the instruments and avionics systems

In between flights there is no check of Pitot tube operation from the cockpit prior to crew arrival.

There was an accident due to incorrect reading of pico sensor

There have been a few accidents where one pitot tube (not pico sensor) was blocked (e.g. by the actions of a mud dauber wasp). This can lead to inconsistent readings in the two pilot's displays and/or with data fed to an autopilot.

One example was Birgenair 301


In theory the pilot in command (the Captain) has responsibility for making sure everything works before flight. On small aircraft responsible pilots always check all instruments and sensors. For example, a pitot tube will be checked to make sure that it is clear and that no spider or mud wasp has taken up residence therein. Another key check is to make sure the antennas are all there and firmly attached. Most checklists have at bare minimum an "instruments" line item and may have many line items for specific instruments. When a pilot does the "walk around" they will specifically examine each and every external sensor such as static ports, etc.

Unfortunately, commercial pilots rarely have time to do such thorough checks, which can be very time consuming for a large aircraft. In many cases they will often not even do a walk around, even if their airline's policy mandates it.

  • 2
    $\begingroup$ your last paragraph is a bold claim with no factual basis. citation needed. $\endgroup$
    – casey
    Jun 12, 2015 at 1:37
  • $\begingroup$ @casey No citation is needed. Next time you take a flight, just watch as the Captain arrives and watch the tarmac. The Captain is supposed to go out the little door and down the stairs and do a walkaround and if he does you will see him. I have been watching flight crews arrive off and on for years and never once have I seen them do a walk around. They just go straight to the flight deck and stay there. $\endgroup$ Jun 12, 2015 at 4:24
  • $\begingroup$ I flew last weekend on 5 different flights and witnessed proper walkarounds. Also, the FO performs walkarounds not the captain. More often than not this is accomplished when the new crew receives the plane, so that the preflight walk around can also accomplish the post flight walk around. I spent 5 years flying for an airline so if we're going to play the game of anecdotes you are far outmatched. $\endgroup$
    – casey
    Jun 12, 2015 at 6:23

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